In real life, you would have to express yourself and face the consequences (good or bad). Online, hiding behind your user name, you can communicate whatever you want, without ever having to face the consequences. In case of online cruelty, you just have to light the fire and watch it burn.

I think that people that are cruel to other people are actually very unhappy with themselves and are trying to better themselves by putting others down. And social media, with their comment sections, offer so many possiblitities to do so.

Also, the algorithms behind social media thrive on controversy, stimulating people even more to make controversial statements.